The objective of this work is the development of a prototype solid- state ultraviolet light source, to be used as a fluorescence excitation source in a variety of biomedical instruments. This device will be the first practical solid-state ultraviolet light source, and is expected to have the advantages typical of a solid- state device, and to be superior to conventional gas-discharge ultraviolet lamps. The device will be based upon the technology of double-insulated thin-film electroluminescence, similar to that used in the commercial manufacture of flat-panel computer displays, but employing novel materials producing ultraviolet rather than visible light emission. The device is intended to replace conventional low-pressure gas-discharge lamps (particularly mercury-vapor lamps) in existing applications such as electrophoresis gel transilluminators and clinical fluorescence assay instruments, and to enable new applications such as battery- powered fieldportable fluorescence microscopes for tropical medicine as a result of its unique properties. The device will be developed in collaboration with a major government laboratory working in the field of thin-film electroluminescence, and with a major commercial manufacturer of biomedical research instrumentation.